Two pipes can fill a tank in 6 hours and 8 hours respectively. A third pipe can empty the same tank in 12 hours. If all the pipes start working together, how long it will take to fill the tank?

4.8 hours

The following chart has to be made first:

Efficiency of A = 4

Efficiency of B = 3

Efficiency of Leakage = -2

Efficiency of A + B + Leakage = 5

Thus, it will take 4.8 hours for the cistern to be filled = \(\frac{24 }{ 5}\) = 4.8 hours